The invention relates to a device and method for preparing the evisceration of beheaded slaughtered poultry.
In poultry processing plants slaughtered and defeathered poultry is conveyed to an evisceration device for eviscerating beheaded slaughtered poultry having a carcass with a body cavity having a breast side and a back side, as well as a vent end where the vent is or was located, and at least part of the neck with a neck opening at a neck end thereof, the slaughtered poultry having a viscera pack including heart, lungs, liver, stomach, intestines, trachea (windpipe) and esophagus (gullet) including crop, including a part of the esophagus and trachea at the neck side of the crop. In order to eviscerate, the body cavity is opened at the vent end, which vent end opening is made by a separate vent end opening device upstream of the evisceration device or a vent end opening device that is integrated with the evisceration device.
In many common evisceration methods the carcass is retained in an orientation with the neck end downwards, e.g. in an approximately vertical orientation or retained in a tilted orientation. This neck end downward orientation is more practical than an orientation wherein the vent side is oriented downward. The latter orientation causes, or may cause, the viscera pack (or a portion thereof) to spill uncontrolled from the body cavity which is not, or hardly, the case when the neck downward orientation is used. Also the vent end downward orientation requires a rather complex retention structure of the evisceration device as the carcasses are commonly conveyed hanging from their legs. An example of a vent end downward orientation is e.g. found in U.S. Pat. No. 6,328,645.
In common evisceration methods an eviscerating tool is entered into the body cavity of the retained carcass via the opened vent end. The eviscerating tool is dipped deeper into the body cavity in a path along the breast side of the body cavity so that the front end thereof passes the viscera pack at least till beyond the liver, commonly till below the heart, e.g. to clamp the esophagus (gullet) close to the neck end by means of a clamp at the front end of the eviscerating tool if present. Then the eviscerating tool is withdrawn and thereby the viscera pack is lifted out of the body cavity.
An early example of an evisceration device for automated removal of the viscera pack is disclosed in U.S. Pat. No. 3,798,708. Herein an evisceration tool is dipped into the body cavity and passed in an arc along the breast side of the body cavity to avoid damage to internal organs. With reference to FIGS. 15 and 16 therein an evisceration tool is disclosed embodied as a loop having parallel legs connected by a bight forming the front end of the tool.
The eviscerating tool is dipped into the body cavity until the bight reaches the lungs, which are deep in the cavity close to the neck end. Then the eviscerating tool is withdrawn along the backbone and in this process the gizzard and the rest of the viscera pack is trapped between the legs of the tool. The further withdrawal causes the entire viscera pack to be removed from the body cavity.
In a bird's digestive system, the crop is an expanded, muscular pouch near the gullet or throat. It is a part of the digestive tract, essentially an enlarged part of the esophagus. The crop is used to temporarily store food. Generally, poultry that is about to be slaughtered is kept void of food for some time, as a result of which the crop of slaughtered poultry is supposed to be empty. The crop is generally positioned in the décolletage between the breast fillets, adjacent the tip of the breastbone, and hence also adjacent the furcular. The crop itself is fragile and vulnerable, whereas both ends of the crop are firmly connected to the esophagus and trachea: one end adjacent the body cavity and opposed thereof at the neck side. In general, the evisceration tool contacts the crop connection at the end adjacent the body cavity.
The prior art evisceration methods and devices are found to be unsatisfactory in view of contamination by remains and contents of the crop. At present day operating speeds of eviscerating devices are very high and losses due to crop contamination are witnessed in the range between 30 and 60 percent.